Reenforced-concrete slab



w. E. IRVING REENFORCED CONCRETE SLAB Feb. 10. 1925.

Filed April 1.

dill

Patented Fen. MD, 1925.

UNHTED STATES rarest cornice.

wan'rnn. n. ravine, or onnnnnoon, oon'n'norrenr, Assrenon 'ro ravine anon wonns consen a conronarron or new roan.

EMNFQRCED-GONCRETE SLAB.

Application filed a t-n i, 1924-. Serial to. 703,377.

material which can be manufactured in, standardized form, and which, in addition to armored wearing or tread surfaces, will also contain metallic reinforcing elements, and be relatively light in weight as com pared with other reenforced concrete slabs of even inferior strength and wear resisting qualities.

A typical use to which my invention may be advantageously applied is in the flooring of bridges subjected to heavy trafic conditions, in which very thick slabs of ordinary reenforced concrete are now often used.

Such old forms of concrete slab have to be made of excessive thickness (8 to 10 inches or more) to successfully resist the applied bending stresses, so that they add an un-- necessary weight to the dead load which the supporting bridge structure has to carry,

and, at the same time, are unsatisfactory because of constant liability to fracture under impact, or from seasonal changes of ternthinner and yet be self-supporting under given loads, and which present armored wearing surfaces to the trafic that will last' practically indefinitely, and which have excellent holding qualities against the 'traotive thrust of motor driven vehicles.

The best form of structure, at present known to me, embodying my invention, and one of sundry ossible modifications thereof, is illustrated ofdrawings in which:

in the accompanying sheet Fig. 1 is a plan view of the metallic "skelej o my invention,

Fig. 2 is a side elevatzon and 3 is a cross section of the same drawn to difierent scales.

Fig. 4; is a perspective, illustrative view of a completed panel with parts broken and,

Fig. 5 is a cross section of a modified form with parts broken away.

Throughout the drawings like reference characters indicate like parts. The preferred form of grating here shown is that described and claimed in U. S. patent to Keller No. 1,045,795, granted November 26, 1912, though other forms might be used. This preferred form of grating is composed of a series of straight bars 1, 1, spaced apart and held to ether by a series of intermediate bent, or reticulated, strips of metal, 2, 2, of less depth, all said parts being fastened thereto by. rivets 3, 3, or equivalent-means. In the simplest form of the invention the grating is concrete 4 (Fig. 4) or other mastic 5, (Fig. 5) with that surface of the grating in which the adjacent edges of bars 1, 1, and strips 2, 2, arefin the same plane, located substantially in the plane of theupper surface of the completed slab so formed- Such grating then helps to form an armored tread surface for the slab which is highly resistant to the wearin effect of the feet of pedestrians, or of t e wheels of vehicles, passing over it. Also the grating gives strength to the completed structure for resisting bend-' ing, will then form keys or fins passing through these holes and firmly unit ng the otherwise partially se arated bodies of said concrete or mastic, t us keying the whole mass to the grating, as shown at8 in Fi 4.

Panels thus constructed, without a ditional elements in the combination, may be used for stair treads and in other situatlons, with or without a complete underlying foundation or support, where the production of durable, non s1ipping tread surfaces is the main consideratwn,

embedded in a plastic mass of Where slabs of greater thickness or depth are required to act as trusses, supported only t their ends, and to then support heavy loads particularly moving loads, as in trafiic bridges, it is desirable to additionally strengthen the slab by a bottom member which will both serve to further assist in holding the mastic-in place in the meshes of the tread surface forming grating, and also serve as the lower, tension member of the truss so formed.

This may best be done by also embedding, in or near the bottom surface of the slab, a second panel of grating 7, as shown in Figs. 2, 3, and 4. If the preferred form of grating shown in the Keller patent is used for this purpose, such second and lower grating 7 may best be reversed in position, as shown, so that the reticulated strips 2, 2, will then be in the lowest possible position in the slab and have the greatest possible bending moment with reference to the upper grating which, of course, serves as the compression member of the truss and center of any bending moment produced by loads superposed thereon. This also has the advantage that two armored surfaces are then formed on the slab, and the same can consequently be used with either side up.

To further strengthen the structure the two gratings may be spacedapart and held together by metal struts, 9, 10 and 11, some of which, as shown at 9 and 11, are oppositely inclined one to another and to the gratings to produce an effective bracing action, while others, as 10, are placed at right angles to the gratings to ensure accurate spacing of the same, and also to produce a composite bracing system, by. cooperation with the inclined struts 9 and 11. These struts may be conveniently fastened to the respective gratings by rivets placed in properly selected holes of the extra series 6, 6, provided in the straight bars 1, 1, as above explained.

As indicated in Fig. 4 the originally plastic, subsequently hardenedbody of the slab is preferably formed of a good quality of concrete (such as is usually made of hydraulic cement mixed with sand and other mineral aggregate) where great strength and wear resisting qualities are required, but in some other cases I may use a softer mastic (an asphaltic compound, perhaps) such as shown in Fig. 5. This latter may be advisable where sound deadening qualities ora semi-elastic tread surface is desirable.

Under any of these conditions the lower grating 7 may be replaced or supplemented by some other form of retaining member. For this purpose I may use asheet of metal 12, shown in Fig. 5 and this may be made of metal thick enough so that its outer edges (one of which is shown at 13 in Fig. 5)

- may be bent up to serve as the outer memers of the series of straight bars 1, l, of the grating. thus saving material, as well as labor in riveting.

In constructing a slab or plate according to my invention the metal skeleton, such as shown in Figs. 2, 3, and 4:, or other form of metal frame or container such as shown in Fig. 5, or the upper grating alone, is first rivetedtogether, and the spaces thereafter filled in with the plastic material and the same allowed to set before use. In the form shown in Fig. 5 this filling operation may be performed after the metal structure is installed in its position of use. The gratings can be cheaply manufactured in standard units by quantity production in properly equipped plants and then shipped on order in knocked down condition to the location of use, where they may be assembled and the bracing struts 9, 10 and 11 riveted in position, if it is important to economize bulk in transportation or the complete skeleton may be riveted together at the production plant, if the resultant saving in labor exceeds the alternative saving in freight. In either case the filling mastic will usually be mixed and added on the job to save freight.

It should be understood that the accom panying drawings are illustrative. only, and are not supposed to show exact dimensions or proportions. Thus the structures shown in Figs. 3 and 4 are much narrower in proportion to their depth than the actual structures would usually be in good practice. In general it may be said, however, that slabs or plates of my improved construction can usually be made of about half the thickness of the ordinary reenforced concrete slabs now in use for any given purpose, and de velop the same or greater strength under bending stresses and far greater lasting qualities. and that, while the metal gratings have a greater specific gravity than the concrete, which they displace, they weigh but little more than the old form of reinforcing rods usually employed, and that they occupy such a small proportion of the total mass of the slab that a large net saving in weight results. Consequently a heavy traffic bridge structure may be redesigned when my invention is used and enough metal saved in the supporting structure (whether of the cantilever, girder or suspension type) to more than compensate for the additional cost of my improved armored floor plates or slabs. and to this saving in first cost is added still greater savings in upkeep and replacement of the roadway surface under use. and longer life.

It is also to be understood that my invention is not limited to the particular form or outline of grating shown in the drawings but that gratings of any desired design or structure may be substituted for that shown,

reasons a that other forms and arrangement of bracing struts may be employed, and that other forms of fastening means may be substituted for the rivets shown.

A special advantage which the use of my invention produces, over old methods of building reenforced concrete slabs, results from the fact that in my invention the reinforcing metal is accurately spaced and se curely held in the predetermined position in the slab by reason of the spacing action of the struts, 9, 10 and 11 or equivalent spacing means used, and because the elements of the grating are fixed in their relative positions. This is a decided improvement over the loose rods, etc., heretofore used, which are often displaced before the pouring of the concrete, or by the act of pouring it, so that they do not have the expected strengthening edect on the com pleted slab. Also my grating structure I alone forms a sufficient flooring over which and dead weight thereby saved.

motor trucks or wheel barrows carrying the plastic concrete or other filling may be run to dump it into the metal skeletons after they have been placed in position to form the bridge or other flooring, any convenient retaining means, such as boards, metal lath,

etc., being fastened against the under surface of the grating skeleton in the usual way to prevent the semi-liquid mass from falling entirely through the floor structure.

A saving in necessary thickness of slab, over ordinary reenforced concrete, also results from the added strength in resisting compression stresses given to the upper portion of each slab by the upper grating. While the rods of ordinary. reenforced concrete slabs, collected in the bottom portions thereof, ma make that portion strong enough to withstand the tensile strains produced by the bending moment, the unreinforced upper portions of suchslabs may be crushed by the compression stresses there produced. In my invention the ting reinforcement at such upper portion of the slab supplies ample protection against any such failure -under compressive stresses, and, as a result the slabs may be madethifn-ner,

All embodiments of my invention above described form plates or slabs of trusslike character that are self-supporting in thesense that they are capable of functioning, as trusses and carryin relatively heavy. loads when supported on y at their ends.

Having described my invention, I claim: 1. As a new article of manufacture, an armored slab forming a com osite late and truss suitable for use as floorin an or heavy duty, which slab comprisesa y of originally plastic material hardened in position about the members of a metallic grating, 4 said grating being composed of straight bars of considerable depth with intervening bent.

and subjected to heavy duty,

out in claim 6, in which said second strips of less depth riveted to" the straight bars in position such that the upper edges of both are in the same plane.

2. A new article of manufacture, such as is set out in claim 1, in which said grating is keyed in said slab by fins of the hardened. material passing through openings in certain elements of the grating.

3.As a new article-of manufacture, an armored slab or plate suitable for use as flooring, treads-or paving, which slab or plate comprises a body of originally plastic but subsequently hardened material with a metallic grating set in said hardened material, which grating is composed of bars and strips of different depths with the upper edges of all bars in-the plane of the upper surface of said slab or plate, to ether with a metal sheet extending and held under the bottom edges of the deeper bars of said grating.

4. As a new article of manufacture, an armored slab, or plate suitable for use for flooring, treads or paving, which slab or plate comprises a panel of grating having a series of p-arallel,straight bars of considerable depth connected together by a series of strips of less de th, the 11 per edgesof said bars and strips eing in t e same plane, a body of hardened mastic filling all the spaces between said strips and bars, and a sheet of metal extending across the bottom of said series of straight bars and connected to the exterior members of said series.

5. As a new article of manufacture, an armored slab forming a composite plate and truss suitable for use as a flooring when resting on separated supports and subjected to heavy duty, which slab or plate com rises a panel of grating having a series 0 parallel, straight bars of considerable depth connected together by a seriesv of strips of less de th, the upper edges of said bars and strips ing in the same lane, a body of herdened mastic filling) al the spaces between said strips and are, and additional metallic reinforcing and retaining meansfor the lower portion of said mastic body.

6. As a new article of manufacture, an armored, reenforced slab forming a composite plate and truss suitable for use as a flooring when resting on separated supports bod f whicl'ilslabi or 0 011 na y p ashali'dened m aterial with plate comprises a tic but subsequently two metallic gratings set in said hardeners sai -1 gratings being substantially'fiush with the material, the upper surface of one of upper surface of said slab.

7.,An. article of manufacture, such as set ating has its lower surface substantially ush with the lower surface of said slab.

8. An article of manufacture, such as set out in claim 6, in which said two gratings are spaced apart and held together by metallic struts. I

9. An article of manufacture, such as set out in claim 6, in which said two gratings are spaced apart and held together by metalhe struts,- some of which struts are inclined to said gratings andoppositely inclined one to the other.

10. An article of manufacture, such as set out in claim 6, in which said two gratings are spaced apart and held together by metallic struts which are fastened at. either end to said gratings by certain rivets also serving to fasten together constituent elements of said respective gratings.

' use in 11. A metal skeleton adaptd for use in armorin and reinforcing a slab designed for oors and for like purposes, which skeleton comprises, in combination, ,two

for spacing apart and holding together said gratings, the upper grating being a rigid.

structure capable of acting as a compression resisting member in any composite truss structure in which said skeleton may be incorporated.

12. A structure such as set out in claim 11 in which certain of said struts are 1nclined one to another and to the planes of the gratings.

13. A structure such as set out in claim 11 in which certain of said struts are inclined one to another and to the planes of the gratings, while others are placed at right angles to said planes.

\VALTER' E. IRVING. 

